package ch8.AdjGraph;

import java.lang.*;
import java.util.*;

public class BFS {
    static final int MAXV = 100;    //表示最多顶点个数
    static int[] visited = new int[MAXV];   //访问标志数组

    public static void BFS(AdjGraphClass G, int v) {   //图G从顶点v出发的广度优先遍历
        ArcNode p;
        int w;
        Queue<Integer> qu = new LinkedList<Integer>(); //定义一个队列
        System.out.print(v + " ");  //访问顶点v
        visited[v] = 1;             //置已访问标记
        qu.offer(v);                //v进队
        while (!qu.isEmpty()) {     //队列不空循环
            v = qu.poll();          //出队顶点v
            p = G.adjlist[v].firstarc;  //找顶点v的第一个邻接点
            while (p != null) {
                w = p.adjvex;
                if (visited[w] == 0) {          //若v的邻接点w未访问
                    System.out.print(w + " ");  //访问顶点w
                    visited[w] = 1; //置已访问标记
                    qu.offer(w);    //w进队
                }
                p = p.nextarc;      //找下一个邻接顶点
            }
        }
    }

    public static void main(String[] args) {
        AdjGraphClass G = new AdjGraphClass();
        int n = 6, e = 7;
        int[][] a = {{0, 1, 1, 0, 0, 0},
                     {0, 0, 0, 0, 0, 1},
                     {0, 0, 0, 1, 1, 1},
                     {0, 0, 0, 0, 0, 0},
                     {0, 0, 0, 1, 0, 0},
                     {0, 0, 0, 0, 0, 0}
        };
        G.CreateAdjGraph(a, n, e);
        System.out.println("图G");
        G.DispAdjGraph();

        System.out.print("BFS: ");
        Arrays.fill(visited, 0);    //初始化所有元素为0
        BFS(G, 0);
        System.out.println();
    }
}
